Objective: The structural anisotropy of articular cartilage controls its deformation response. As proteoglycans and collagen vary with depth, simple uniaxial compression results in inhomogeneous deformation with disti...Objective: The structural anisotropy of articular cartilage controls its deformation response. As proteoglycans and collagen vary with depth, simple uniaxial compression results in inhomogeneous deformation with distinct depth-dependent mechanical properties. Investigations into depth-dependent mechanical properties of articular cartilage have previously required tissue modification after specimen isolation. Such modifications include histological processes, freezing, subchondral bone removal, and fluorescent staining that may alter the tissue, limiting in vivo applicability. Design: Using a custom tissue-sectioning device, 0.1 mm thick unfixed, unstained, osetochondral samples were obtained. A customized apparatus loaded samples to 12.5%, 24%, and 29% compression in under a microscope with 10× magnification. Equilibrium load was measured after stress relaxation. Intra-tissue displacement was measured by tracing groups of cells between the different compression levels using a digital imaging program. Cell distance from the subchondral bone was measured to identify intratissue displacement and calculate strain. Results: The results reveal that stress levels and intratissue displacement increased with greater tissue compression (p p in vivo conditions and may provide an important method for analyzing the coordinated changes in cartilage composition and function due to ageing and disease.展开更多
Introduction: Analgesia following shoulder surgery commonly uses interscalene nerve blockade. When contraindicated (i.e. respiratory compromise), suprascapular nerve blockade can provide a viable alternative. Although...Introduction: Analgesia following shoulder surgery commonly uses interscalene nerve blockade. When contraindicated (i.e. respiratory compromise), suprascapular nerve blockade can provide a viable alternative. Although a number of techniques have been used, Barber in 2005 described a simple method using anatomical landmarks. While theoretically straightforward, substantive evidence supporting the advantages attributed to the technique has yet to be identified. The present study anatomically examines the technique proposed by Barber to critically assess its potential to benefit clinical practice. Materials and Methods: Using the technique proposed by Barber in 2005, the Nevaiser portal was used to introduce a K-wire into the supraspinous fossa in the region of the suprascapular nerve. A spinal needle was inserted in the same manner and left in position in the presumed region of the transverse scapular ligament. Tissue was dissected out around the wire and needle to visualize their proximity to the suprascapular nerve and transverse scapular ligament respectively. Results: The K-wire was consistently located close to the suprascapular nerve with all cases being within 5 mm. Spinal needle placement relative to the transverse scapular ligament was variable with 50% anterior, 25% posterior, and 25% displaced (likely due to dissection). Conclusions: The results illustrate that it is possible to reliably place a needle close to the suprascapular nerve using the technique described by Barber in 2005. This study provides anatomical confirmation of Barbers description of a simple technique and the basis for clinical study.展开更多
文摘Objective: The structural anisotropy of articular cartilage controls its deformation response. As proteoglycans and collagen vary with depth, simple uniaxial compression results in inhomogeneous deformation with distinct depth-dependent mechanical properties. Investigations into depth-dependent mechanical properties of articular cartilage have previously required tissue modification after specimen isolation. Such modifications include histological processes, freezing, subchondral bone removal, and fluorescent staining that may alter the tissue, limiting in vivo applicability. Design: Using a custom tissue-sectioning device, 0.1 mm thick unfixed, unstained, osetochondral samples were obtained. A customized apparatus loaded samples to 12.5%, 24%, and 29% compression in under a microscope with 10× magnification. Equilibrium load was measured after stress relaxation. Intra-tissue displacement was measured by tracing groups of cells between the different compression levels using a digital imaging program. Cell distance from the subchondral bone was measured to identify intratissue displacement and calculate strain. Results: The results reveal that stress levels and intratissue displacement increased with greater tissue compression (p p in vivo conditions and may provide an important method for analyzing the coordinated changes in cartilage composition and function due to ageing and disease.
文摘Introduction: Analgesia following shoulder surgery commonly uses interscalene nerve blockade. When contraindicated (i.e. respiratory compromise), suprascapular nerve blockade can provide a viable alternative. Although a number of techniques have been used, Barber in 2005 described a simple method using anatomical landmarks. While theoretically straightforward, substantive evidence supporting the advantages attributed to the technique has yet to be identified. The present study anatomically examines the technique proposed by Barber to critically assess its potential to benefit clinical practice. Materials and Methods: Using the technique proposed by Barber in 2005, the Nevaiser portal was used to introduce a K-wire into the supraspinous fossa in the region of the suprascapular nerve. A spinal needle was inserted in the same manner and left in position in the presumed region of the transverse scapular ligament. Tissue was dissected out around the wire and needle to visualize their proximity to the suprascapular nerve and transverse scapular ligament respectively. Results: The K-wire was consistently located close to the suprascapular nerve with all cases being within 5 mm. Spinal needle placement relative to the transverse scapular ligament was variable with 50% anterior, 25% posterior, and 25% displaced (likely due to dissection). Conclusions: The results illustrate that it is possible to reliably place a needle close to the suprascapular nerve using the technique described by Barber in 2005. This study provides anatomical confirmation of Barbers description of a simple technique and the basis for clinical study.
